The effect of irradiation by gamma ray on the structural and optical properties of nickel oxide nanoparticles prepared by sol-gel method.

Abstract

In this work, NiO, NPs were synthesized using the Sol-Gel technique at various molar ratios of nickel nitrate and citric acid ($P_1$, $P_2$ and $P_3$) and annealed at 525°C, and study the effect of irradiation on the structural and optical properties of nickel oxide nanoparticles. According to the XRD data, every sample is polycrystalline, with a cubic structure as its preferred orientation (200) plane. And that these results largely agree with the standard card (ICSD No. 047-1049). And when comparing the behavior of the grains before and after irradiation, we notice that there is an increase in the intensity of the diffraction peaks for all prepared samples compared to what it was before irradiation. The results showed that the grain size was less than it was before the irradiation, and this means that the irradiation caused an increase in the crystallization of the grains and thus a decrease in the size of the crystals. (FESEM) images of nickel oxide nanoparticles before and after irradiation showed that irradiation reduces the size of the granules except for the sample ($P_3$), which shows the opposite and these results. The optical results showed that the gamma ray irradiation process led to a slight increase in the absorbance and absorption coefficient, as well as a decrease in the optical energy gap.